In the field of mobile devices, such as cellular telephone and Blackberries, a small form factor is an increasingly important design consideration. Such devices typically include battery packs having power lines and input/output lines. In some instances, however, the small form factor of battery packs makes it difficult to provide sufficient pins for communicating.
Accordingly, it is known to provide a combined power and input/output pin or pins on an integrated circuit or other device. Such solutions typically include a diode and capacitor or a resistor and capacitor to extract power and store it for the device.
The diode-capacitor solution, however, has proven to be disadvantageous in low voltage systems. More particularly, in such systems, the diode drop may be insurmountable.
The resistor-capacitor solution is disadvantageous owing to baud rate and power consumption contention. That is, low power consumption requires large resistors which require longer on-times and lower baud rates which increase power consumption.
As such, there is a need for a system and method for minimizing the pins for communicating between a power supply and target device. In particular, there is a need for an improved combined power and input/output solution.